Printed circuit key improvement

ABSTRACT

Magnetic reed switches have their operation strokes standardized by locating the reeds in variable positions relative to a magnet affixed in a movable structure depending upon their individual switching characteristics. Switching structure disclosed includes both a movable magnet holder and a reed holder for referencing the stroke position. Also disclosed is an automatic system for referencing reed switches out of a variable batch for identical operating conditions.

United States Patent- Inventors John Paul Jones, Jr. Wayne; Peter A. Peroni, Pottstown, both of, Pa. Appl. No. 863,496 Filed Oct. 3, 1969 Patented Aug. 24, 1971 Assignee Naveor, Inc.

Norristown, Pa.

PRINTED CIRCUIT KEY IMPROVEMENT 9 Claims, 5 Drawing Figs.

US. Cl 335/205, 29/593, 29/622, 73/111 Int. Cl ..H0lhlll00,

' H01 h 45/02 Field of Search 335/205,

MARKING DEVICE IMJMAGNET [56] References Cited UNITED STATES PATENTS 3,251,962 5/1966 Jones, Jr 335/153 3,462,719 8/1969 Peroni et al 335/206 Primary Examiner-Bemard A. Gilheany Assistant Examiner-R. N. Envall, Jr. Attorney-Laurence R. Brown SWITCH CONTRDLLED DRIVE MARKING REVERSIBLE R MOTOR START sum CONTROL STOP PATNI EB mszmn 3.601. 728

sum 1 0F 2 Y l 1mg 14A FIG .l

MARKING DEVICE R l5 I2 I4 63 l M E m 4 -4- so n MAGNET 6| 64 SWITCH CONTROLLED DRIVE- MARKING DELAY 66 67 Amnmw R REVERSIBLE R T MOTOR ESE I F s 70 65 TAR T STO ,.Y... .E i CONTROL W .V ..E, .H v. ..4.. M w, k. .o... JOHN PAUL JONES,JR.

Fl (5 .5 PETER A. PERONI BY A4 60 ATTORNEY I NVENTDRS JOHN PAUL JONES ,JR. PETER A. PERONI BY Ogwvw-A/ ATTORNEY PRINTED CIRCUIT KEY IMPROVEMENT I This invention relates to magnetic reed switches operated by movable magnets and more particularly it relates to means and methods of standardizing relative to a movable magnetic field the switching position of individual reed switches taken from a batch with varying switching characteristics.

When switching devices responsive to a movable shaft are used in some critical operations, including keyboards for example, it is desirable to precisely locate a switching operation at the same stroke position from one switch to the next.

Keyboard switches using magnetic reeds have been accepted in the art, but keyboards using such switches have not always been acceptable without careful watching of switches because of variations in length of stroke from one key to another caused by variations in reed switch characteristics.

Accordingly the object of this invention is to produce means and methods of standardizing the operation stroke of magnetically operated reed switches.

Therefore in accordance with the invention, each reed switch is referenced along its axial length for positioning of the reed in a switch assembly at a position where it will operate at a standard stroke point. I

' Further features, objectives and advantages of the invention are discussed hereinafter with reference to the embodiments set forth in the accompanying drawing, wherein:

FIG. 1 is a sketch illustrating the variations in switching characteristics of reed switches,

FIG. 2 is an exploded perspective view of a reed switch assembly provided in accordance with the invention,

' FIG. 3 is an elevation view of a movable magnet holder assembly provided in accordance with the invention,

FIG. 4 is a reed switch holder assembly provided in accordance with the invention, and

FIG. 5 is a schematic diagram of an automated referencing position system for producing an individual mounting reference position based upon the switching characteristics of a reed switch.

FIG. 1 displays at relative axial positions normal to a reference line 10, a magnet 11 and two reed switches 12 and 12', which may be switched by relative axial movement of the switches and magnet. Since the reed switches are sometimes very small being disposed within one-sixteenth inch diameter nonmagnetic glass tube housing members enveloping contacting portions 13 with axial leads 14, 15 extending from the ends of the glass tube, it is difficult to manufacture or select such switches at reasonable cost so that the switching point is reached identically by relative position with magnet 11 which produces a field influencing the reeds within the glass housing. As noted switches 12 and 12 may have significantly different axial positions at the switching point so that differences in stroke distance would result in switching in a keyboard between different switches unless relatively selected for uniformity. In accordance with this invention however the switches are selected by referencing the switching position such as by marking the leads as they cross reference line 16, as denoted by the dots, so that they may be used where strokes are maintained substantially identical in any relative axial movements between magnet 11 and reed switches 12 to and from a switching operation.

FIG. 2 shows in exploded form a keyswitch embodiment incorporating the standardized stroke feature of this invention. A plastic housing comprises a plastic bottomside member and the mating member 21 having interfitting tabs 22, 23 and 24 which register in slots 25, 26 and 27 where they may be heat sealed, frictionally engaged or glued in place. Channelways 28 guide inside the housing a plastic magnet-holding movable member 29 which retains magnet 30 in a fixed position therein by means better seen in Figure 3, comprising the solid rest pedestal 31, two flexible rolled lips 32, 33 and flexible frictional top tab 34. The body is essentially a rectangular plastic plate 35 in a plane including the axis of movement of the shaft 36 against spring 37 centered on boss 38. Spring 37 surrounds centering tab 39 on plate 35. Two guiding tabs 40 and 41 ride in channels 28 to maintain the magnet 30 comprising a cubic structure with an indented cylindrical face 42 which registers about the glass cylinder of switch 12 held in a groove 43 in the inside surface of housing member 20. The magnet is held in the rectangular aperture 44 by frictional contact with flexible tabs 32, 33 and 34, and is moved by a key (not shown) attached to the top of shaft 36 which extends from aperture 45 in housing member 21.

In accordance with this invention, the shaft 36 may be depressed to a fixed position where the switching operation is desired by a jig or the like engaging shaft 36 to hold it down by compressing spring 37. Then the reed switch 12 may be pushed into groove 43 far enough to switch and plastic housing member 20 can be thermally melted against the lead 15 to hold it in a fixed position.

Altemately a reference magnet can be used to afiix a switch 12 into a plastic support member by the same procedure at position 51 as shown in FIG. 4. A yoke wire 52 is welded to switch lead 14 and has extensions passing through support member 50 to form the three leads 15, 14A and 14B for connection to external electrical circuits. This support member may be inserted into grooves shown in the housing of US. Pat. No. 3,462,719 commonly assigned and issued Aug. l9, 1969 to Peter A. Peroni and John Paul Jones Jr., for example, alongside a magnet holder such as 29 shown in FIG. 3.

As shown in Figure 5, the method and standardized reed switches of this invention may be produced by automated equipment. For this purpose brushes 60, 61 can use electrical signals caused by the switching of reed contacts for controlling a marking device 62. This marking device 62 may bend the leads, seal the leads into a plastic matrix or weld the leads in position on a frame or in a holder, all at an individual position for each switch 12 that specifies the exact switching position along a stroke that is simulated by moving switch 12 along an axis 63 by means of movable push rod 64 for example, until the switching operation takes place, at which time movement can be stopped for marking by a signal at lead 65 which controls the motor 66 to drive rod 64 by means of screw 67. After marking, the switch pulse delayed in circuit 68 may be used to reset for another cycle by reversing motor 66 to replace the push rod 64 at a limit shown by switch 69. The cycle may be started again by starting the motor with switch 70.

It is evident that in this automated machine, standardized switches may be designated from a variable batch, thus avoiding rejects and permitting use of less expensive switches and smaller switches, which are important in keeping the size of keyswitches as shown in FIG. 2 small. Similarly the keyswitch body itself may be used as a partial jig for the process, and each switch and reed is identifiable by the marking process mounting switches in variable positions along the reed axis. Thus the art is improved and features of novelty are claimed.

What we claim is:

1. A reed switch standardizing assembly comprising in combination, a magnet, a movable assembly holding said magnet thereon in a fixed position, one magnetic reed switch having two axial magnetic reeds extended from a nonmagnetic enclosure about a switching contact position where the two reeds engage each other by force of a magnetic field influencing the reeds, a batch of such reed switches having variations in switching characteristics causing the reeds to engage under different magnetic forces, an assembly holding said one reed switch relative to said movable assembly in a predetermined fixed position, means detecting when the switch closes upon movement of a-magnet adjacent the switch axis and means placing a marking on one reed switch lead signifying the individual switching characteristics of that switch to assure that the stroke of movement of said assembly to operate the switch is substantially identical for different switches in said batch.

2. A switch assembly as defined in claim 1 wherein the movable assembly comprises a flexible plastic member having a substantially plate-shaped framework extending in a plane including an axis of movement, a substantially rectangular aperture in said plate member surrounded by flexible members on three sides, and a magnet held in said aperture by frictional contact with said flexible members.

3. A switch as defined in claim 2 wherein a housing member is provided having guide slots therein engaging mating tabs on said plate-shaped framework.

4. A switch as defined in claim 1 wherein the reed switch enclosure is substantially cylindrical along the reed axis and the magnet comprises a substantially cubic member having a cylindrical slot along one side conforming with the outer cylindrical dimension of said enclosure and arranged on the movable assembly to move parallel to the reed axis adjacent said enclosure.

5. A switch as defined in claim 1 wherein the assembly holding said one reed switch member has at least one plastic member engaging one of said axial leads to reference said predetermined position.

6. A switch as defined in claim 5 wherein the plastic member comprises the bottom and side of a housing member, and a mating housing member is registrable therein for affixing in place by means of interlocking members.

7. The method of standardizing switching positions of individual reed switches having two axial magnetic reeds extended from a nonmagnetic enclosure about a switching contact position where the two reeds engage each other by force of a magnetic field influencing the magnetic reeds taken from a batch of such switches having variations in switching characteristics causing the reeds to engage under different magnetic forces, comprising in combination the steps of testing individually the switching characteristics of said reed switches by relatively moving the switch and a reference magnet over a predetermined path until a switching operation is reached,

detecting a position on the reed axis identifying the position at which the switch closes, and

referencing on at least one of the extending axial leads a marking denoting the detected switching characteristics whereinthe referencing comprises the step of sealing the axial lead in a plastic body.

8. The method of standardizing switching positions of individual reed switches having two axial magnetic reeds extended from a nonmagnetic enclosure about a switching contact position where the two reeds engage each other by force of a magnetic field influencing the magnetic reeds taken from a batch of such switches having variations in' switching characteristics causing the reeds to engage under different magnetic forces, comprising in combination the steps of testing individually the switching characteristics of said reed switches by relatively moving the switch and a reference magnet over a predetermined path until a switching operation is reached,

detecting a position on the reed axis identifying the position at which the switch closes, and

referencing on at least one of the extending axial leads a marking denoting the detected switching characteristics and electrically sensing through said extended leads the switching operation to control said referencing operation.

9. The method defined by claim 8 comprising the step of relatively moving said switch and magnet by automatically controlled positioning means, and effecting said referencing operation as the switching operation electrically sensed. 

1. A reed switch standardizing assembly comprising in combination, a magnet, a movable assembly holding said magnet thereon in a fixed position, one magnetic reed switch having two axial magnetic reeds extended from a nonmagnetic enclosure about a switching contact position where the two reeds engage each other by force of a magnetic field influencing the reeds, a batch of such reed switches having variations in switching characteristics causing the reeds to engage under different magnetic forces, an assembly holding said one reed switch relative to said movable assembly in a predetermined fixed position, means detecting when the switch closes upon movement of a magnet adjacent the switch axis and means placing a marking on one reed switch lead signifying the individual switching characteristics of that switch to assure that the stroke of movement of said assembly to operate the switch is substantially identical for different switches in said batch.
 2. A switch assembly as defined in claim 1 wherein the movable assembly comprises a flexible plastic member having a substantially plate-shaped framework extending in a plane including an axis of movement, a substantially rectangular aperture in said plate member surrounded by flexible members on three sides, and a magnet held in said aperture by frictional contact with said flexible members.
 3. A switch as defined in claim 2 wherein a housing member is provided having guide slots therein engaging mating tabs on said plate-shaped framework.
 4. A switch as defined in claim 1 wherein the reed switch enclosure is substantially cylindrical along the reed axis and the magnet comprises a substantially cubic member having a cylindrical slot along one side conforming with the outer cylindrical dimension of said enclosure and arranged on the movable assembly to move parallel to the reed axis adjacent said enclosure.
 5. A switch as defined in claim 1 wherein the assembly holding said one reed switch member has at least one plastic member engaging one of said axial leads to reference said predetermined position.
 6. A switch as defined in claim 5 wherein the plastic member comprises the bottom and side of a housing member, and a mating housing member is registrable therein for affixing in place by means of interlocking members.
 7. The method of standardizing switching positions of individual reed switches having two axial magnetic reeds extended from a nonmagnetic enclosure about a switching contact position where the two reeds engage each other by force of a magnetic field influencing the magnetic reeds taken from a batch of such switches having variations in switching characteristics causing the reeds to engage under different magnetic forces, comprising in combination the steps of testing individually the switching characteristics of said reed switches by relatively moving the switch and a reference magnet over a predetermined path until a switching operation is reached, detecting a position on the reed axis identifying the position at which the switch closes, and referencing on at least one of the extending axial leads a marking denoting the detected switching characteristics wherein the referencing comprises the step of sealing the axial lead in a plastic body.
 8. The method of standardizing switching positions of individual reed switches having two axial magnetic reeds extended from a nonmagnetic enclosure about a switching contact position where the two reeds engage each other by force of a magnetic field influencing the magnetic reeds taken from a batch of such switches having variations in switching characteristics causing the reeds to engage under different magnetic forces, comprising in combination the steps of testing individually the switching characteristics Of said reed switches by relatively moving the switch and a reference magnet over a predetermined path until a switching operation is reached, detecting a position on the reed axis identifying the position at which the switch closes, and referencing on at least one of the extending axial leads a marking denoting the detected switching characteristics and electrically sensing through said extended leads the switching operation to control said referencing operation.
 9. The method defined by claim 8 comprising the step of relatively moving said switch and magnet by automatically controlled positioning means, and effecting said referencing operation as the switching operation electrically sensed. 